An In-Circuit Test (ICT) process electrically verifies the individual component placement on a printed circuit assembly (PCA). During the ICT process, the verification of light sources is a critical operation that is commonly overlooked due to difficulty and expense. Light source components (typically Light Emitting Diodes or LEDs) provide critical information to the end-user to indicate a warning, fault status, or safe operation.
Currently, there are two major designs for validating optical devices. The LIGHTPROBE™ product from OPTOMISTIC PRODUCTS, Concord, Mass. and the FINN™ product from TEST COACH CORPORATION, Hoffman Estates, Ill., are devices that are tuned to validate a specific color source. However, both of the above devices have high maintenance costs due to their fragile nature. Also, both devices utilize custom sensors that are not readily available as “off-the-shelf” components, and this typically results in a long lead time for each unit that is ordered. Both devices are not able to provide consistent results when observing amber and green light sources. Both devices detect only one color (i.e., the devices are single wavelength dependent) and detect only one light source. It is very expensive to verify a light source by a single sensor. Typically, the cost to verify each light source is about $200 to $400. Additionally, the LIGHTPROBE™ product requires calibration prior to installation and may drift with age.
Additionally, both of the above devices require critical alignment with the light source. The LIGHTPROBE product must typically be placed less than about 0.05 inches from the light source, while the FINN product must be typically placed less than 0.15 inches from the light source.
Thus, the current approaches and/or technologies are limited to particular applications and/or suffer from various constraints.